Access-providing direct suspended ceiling structure with removable locked-in tile sections

ABSTRACT

An access-providing, rigid, properly aligned, suspended ceiling structure for acoustic tiles and the like is described, having removable locked-in tile sections and hidden support structure. The structure employs selectively shaped horizontal parallel beams which have flanges to fit within tile kerfs to provide a tile-supporting structure, which is hidden from view of persons in the room below. Spacer bars extend across between the beams and rigidly anchor them in place. Enlarged ceiling sections are removable by the employment of crossbars sized to fit in tile kerfs between beams with the ends of the crossbars being provided with selectively sized cutouts to permit free longitudinal, unobstructed movement of slidable splines located on the beam flanges. The slidable splines have lengths smaller than tile dimensions supported by the beam flanges and are movable within tile kerfs for ceiling section removal. The horizontal parallel beams are shaped to provide a high load-carrying capability, with their shaping advantageously employed to enhance removability of individual tiles.

United States Patent Kidney 5] Feb. 8, 1972 [54] ACCESS-PROVIDING DIRECTSUSPENDED CEILING STRUCTURE WITH REMOVABLE LOCKED-IN TILE SECTIONS [72]Inventor: Bruce W. Kidney, 57 Montague St.,

Brooklyn, NY. 11201 22 Filed: July 11,1969

211 Appl.No.: 840,910

[52] US. Cl ..52/475, 52/127, 52/484,

52/488, 52/496 [51] Int. Cl ..E04b 5/54 [58] Field ofSearch ..52/144,127, 145,496,484,

Daugherty ..52/627 Primary Examiner John E. Murtagh Attorney-Bryan,Parmelee, Johnson & Bollinger [57] ABSTRACT An access-providing, rigid,properly aligned, suspended ceiling structure for acoustic tiles and thelike is described, having removable locked-in tile sections and hiddensupport structure. The structure employs selectively shaped horizontalparallel beams which have flanges to fit within tile kerfs to provide atile-supporting structure, which is hidden from view of persons in theroom below. Spacer bars extend across between the beams and rigidlyanchor them in place. Enlarged ceiling sections are removable by theemployment of crossbars sized to fit in tile kerfs between beams withthe ends of the crossbars being provided with selectively sized cutoutsto permit free longitudinal, unobstructed movement of slidable splineslocated on the beam flanges. The slidable splines have lengths smallerthan tile dimensions supported by the beam flanges and are movablewithin tile kert's for ceiling section removal. The horizontal parallelbeams are shaped to provide a high load-carrying capability, with theirshaping advantageously employed to enhance removability of individualtiles.

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SHEET '4 UF 4 FIGII INVENTOR BRUCE W. KIDNEY BY EMA )W) ATTORNEYSACCESS-PROVIDING DIRECT SUSPENDED CEILING STRUCTURE WITH REMOVABLELOCKED-IN TILE SECTIONS This invention generally relates to anaccess-providing suspended acoustic ceiling assembly with removablelocked-in tile sections and more particularly to a suspended acousticceiling structure wherein sections of acoustic tiles are selectivelyremovable for enlarged access to a plenum area above the ceiling or forreceiving light fixtures, the supporting structure for the acoustic tilesections being hidden from view of the persons in the room below.

In my U.S. Pat. No. 3,381,437 I have described a suspended ceiling withan invisible support structure whereby access to the plenum area abovethe ceiling becomes possible at any desired location by the convenientremoval of a ceiling tile located below the plenum area of interest.Such individual tile removal capability is obtained by the employment oftile-supporting splines which can be snapped onto the flanges of mainsupporting beams to be slidingly mounted on the flanges and to fitwithin longitudinal slits or kerfs in tile edges to support the tile. Aneasily accomplished longitudinal movement of splines along the flange ofa supporting beam will drop any desired tile out of its position in theceiling.

Among the advantages of this invention are those resulting from the factthat it enlarges the ceiling sections that may be conveniently removedfrom a suspended ceiling structure utilizing the aforementioned splines,to provide large clearance access into the plenum space above theceiling for maintenance personnel and enabling light fixtures to besupported directly from the beams. I

It is a further advantage of the invention to provide a hiddensupporting structure for a suspended ceiling wherein large ceilingsections are removably supported without sagging.

Further advantages of the present invention result from the fact that itenables the selectively shaped horizontal parallel beams to be heldrigidly parallel in predetermined spaced relationship so that thesebeams can be suspended on wires directly from the building structureabove. That is, the horizontal beams and spacer bars provide a rigidgrid without the necessity of employing the heavy structural channelswhich conventionally are installed in the prior art ceilin structures. aI

' The ceiling produced by this invention isdurable, rigid and strong andhides the acoustic tile supporting elements from the viewer locatedbelow the ceiling. The ceiling of this invention further has theadvantage that fewer supporting beams are needed, larger tiles may beemployed, and correspondingly larger access areas are provided upon thremoval of tiles.

In the practice of my invention, the ceiling supporting beams arehorizontally aligned parallel to one another supported on wires directlyfrom the buildings structure and are selectively spaced from each otherand rigidly held in spaced parallel relationship by spacer bars. Thedistance between the spaced parallel beams may span several smallertiles or a single large tile. Each of the supporting beams has alongitudinally extending vertical web which has as its lower edge atile-supporting flange extending generally transversely, i.e.,horizontally, from one side of the web. Sliclable splines are snappedinto place onto the supporting flange, as described in my patent, toprovide movable support members for the acoustic tiles located on theother side of the web where there is no flange. Removable tile sectionsare assembled by employing crossbars fitting into slits or kerfs in theperipheral edges of the acoustic, tiles. The crossbars are angledsections with a cross flange. and are selectively shaped at the endsthereof to allow free passage of the slidable splines. Removable tilesections are formed by placing the cross flanges of two crossbars intooppositely located kerfs of the tile or tiles used in a section.Thereupon, the assembled tile section is inserted from below onto themain supporting beams where it is supported by beam flanges and slidablesplines. The resulting acoustical ceiling includes large removablesections suffrciently sturdy to present a horizontal ceiling free fromsagging tiles and the spaced main ceiling beams are sufficiently strongfor directly receiving light fixtures.

Another feature of the invention contemplatesa suspended ceilingstructure stabilized by the employment of spacer bars. The spacer barsare provided with accurately placed slots sized to engage the supportingbeams and rigidly hold and accurately space the beams from one another.The spacer bars are easily installed to form a quickly assembled rigidsuspended ceiling structure, all of which can be suspended on verticalwires running down from the building structure above, e.g., such as thefloor girders or floor slab above.

A further advantage provided by the horizontal beams employed with theinvention is their increased load-carrying capability. This is obtainedwith an upperedge enlargement and a longitudinal rib along the verticalweb of the beam. The rib provides a selected spacing between tiles tofacilitate movement of splines to remove a tile and advantageously addsrigidity as well as load-bearing capacity to the beam.

The various features, aspects and advantages of the present inventionwill be more fully understood from a consideration of the followingdetailed description in conjunction with the accompanying drawings inwhich:

FIG. I is a perspective view of the accessproviding suspended ceilingstructure with removable locked-in tile sections as seen from the plenumarea above the ceiling.

FIG. 2 is an enlarged perspective view of a portion of the ceilingstructure of FIG. 1 showing the selectively shaped main beams which aredirectly suspendible on wires and are held rigidly in spaced parallelrelationship by the spacer bars, with portions of the acoustical tilebroken away to reveal details.

FIG. 3 is a sectional view taken along the line 33 in FIG. 2 and shownon further enlarged scale.

FIG. 4 is an end view of a direct-wire-suspendible supporting beamhaving a predetermined configuration.

FIG. 5 is a sectional view taken along the line 55 in FIG. I, drawn onenlarged scale and showing an assembly of acoustical tiles andcrossbars.

. FIG. 6 is a sectional view taken along the line 6-6 in FIG. 5 showingdetails of the crossbar. I

FIG. 7 is a perspective view of the ceiling structure as seen from theplenum area above showing the removal of an assembled pair of tiles fromtheir locked-in position between ad: jacent supporting beams.

FIGS. 8A and 8B are respectively an end view and a side view of a spacerbar utilized in rigidly spacing and aligning the main supporting beamsof the ceiling structure according to the invention. I I I FIG. 9 showsthe flexibility of installation capabilities of a ceiling structureembodying the present invention. If structural channels are available,then the main supporting beams can be fastened to such channels by asupporting clip engaged with the beam and channel as shown.

FIG. 10 is an-elevational view taken along the line 10-10 in FIG. 9showing further aspects of the beam-to-channel clip.

FIG. 11 is an elevational view of a beam-to-channel clip of extendedlength. I

FIG. 12 is a perspective view of a main supporting beam and a beamsplicing spline for interconnecting the ends of two beams.

With reference to FIG. I there is shown a direct-wiresuspendedacoustical ceiling structure including a light fixture resting on themain beams of the suspended ceiling, with a plenum area 10 seen abovethe suspended ceiling 12. The ceiling 12 is conveniently andinexpensively supported by a plurality of vertical wires such as 14attached to the building structure above (not shown), such as floorgirders, toggles or shots, known as inserts, in the floor slab above.The wires 14 are attached to main supporting beams 16 which arehorizontally mounted in spaced parallel relationship with one anotherand rigidly held with predetermined spacing. In the ceiling of FIG. 1,the beams are so spaced that pairs of square acoustic tiles may besupported between beams such as tiles 18-18 or an enlarged double-lengthrectangular tile 20 may be employed. A light fixture 22 is shownpositioned between and resting with brackets 23 on the beams 16. Inaddition, there are spacer bars 24 extending across and engaged with thebeams 16 to maintain their predetermined spacing and generally providerigidity to the direct-wire-suspended structure. The spacer bars 24 arespaced at intervals longitudinally of the beams 16.

FIG. 2 illustrates a typical portion of the suspended ceiling of FIG. 1showing a pair of square acoustical tiles 18-18' mounted between a pairof main supporting beams l6--16. Each supporting beam 16 has atile-supporting horizontal flange 26 (see also FIG. 4) on which ismounted a plurality of longitudinally slidable splines 28 of the typedescribed in the above-identified patent. The slidable splines 28effectively provide the opposite sides 30 of the beams 16-16 withsupporting members 32 generally located in coplanar relationship withthe flanges 26 of the beams. This supporting member 32 fits within tilekerfs such as 33 so that one side of tile 18 is supported by theslidable spline 28. The sliding of the spline 28 along the flange 26from the kerf 33 in tile 18 will thereby remove support from that tilethus permitting one edge of the tile to be lowered for removal frombelow. The sectional cutout region of a tile as shown in FIG. 2illustrates that the flange 26 of the beam also fits within a tile kerf33.

Since the spacing, such as S indicated in FIG. 1, between a pair of mainsupporting beams 1616 is equal to twice the size of a single tile. 18, anatural tendency of the pair of tiles l8l8 would be to sag under theirown weight in the middle at their juncture line 34. Such sagging wouldbecome unsightly when viewed from below, and the crossbars 36 serve topro vide tile support for pairs of tiles 18-18 spanned between mainsupporting beams 16-16. These crossbars 36 have angled L-shaped sectionsas seen in FIG. 5, including a vertical web 38 for spacing between themain beams and a cross flange 40 sized and shaped to fit within the tilekerfs. The cross flange 40 extends transversely from the web 38 of thecrossbar 36' and on one side thereof so that a pair of crossbars 36-36(see FIG. 7) engaged in the kerfs on opposite sides of the pair of tiles18l8' define a removable ceiling section.

Each of the crossbars 36 is further'selcctively shaped at the endsthereof so that slidable splines 28 may be longitudinally moved withoutinterference or obstruction by the crossbars. For this reason the lowerportion of the crossbar webs 38 and its flange 40 are selectivelynotched out to a depth D (FIGS. 3 and 6) sized to permit a spline tofreely pass underneath. Thus, the crossbar flanges 40 terminate short ofthe end of the webs 38 by a distance E selected to allow the entirespline including its supporting member 32 to freely slide by it. It isnoted in FIG. 3 that the upper portions of the crossbar webs. 38terminate closely adjacent (distance A) to the sides of the mainsupporting beam 16 to prevent any significant sliding motion of thecrossbar 36 such as would cause interference with the longitudinallyslidable splines 28.

In order to stabilize the ceiling structure, spacer bars 24 (see FIG. 2)are employed at spaced intervals along the supporting beams 16 tomaintain the spacings S between the beams as well as to hold and lockthe main beams against twisting or displacement. A spacer bar 24 isillustrated in FIG. 2 and is shown to snugly fit and engage in lockingrelationship about an upper box beam section 42 of a pair of mainsupporting beams 16. The spacer bar is an angled bar of inverted L-shape which at the ends thereof is provided with slots which aregenerally T-shaped, having an enlarged head sized to engage the box beamenlargement 42 of the beam 16 and for engaging the sidewalls of thebeams in locking engagement as will be described in relation to FIG. 8.

With reference to FIG. 4, the main supporting beam 16 configuration isclearly illustrated. It includes an upper enlargement 42 in the form ofa rectangular box beam section. A vertical web 44 interconnects the boxbeam enlargement 42 with the horizontal supporting flange 26. The web 44is further provided with an offset protrusion 46 laterally extending onthe side of the web 44 opposite from the side to which the flangeextends to slightly offset the joint line between the tiles as is moreclearly illustrated in the adjoining FIG. 3. This lateral protrusion,i.e., longitudinally extending rib section 46, is shown as havinggenerally a rectangular channel shape, and it advantageously cooperateswith the flange 26 to stiffen the lower portion of the web 44 againsttwisting or deflection. The beam 16 is lightweight but strong and stiff,having sufficient strength for direct suspension from vertical wires 14without the use of structural channels. Moreover, these beams 16 havesufficient strength for supporting the light fixtures 22 having a widthS, which in this example is 2 feet. Apertures 48 are formed at spacedintervals along the web 44 for the attachment of direct supporting wires14, as seen in FIGS. 2 and 3. 1

In the FIG. 3 it may be observed that tiles 18 are each provided with aperipheral kerf 33 separating upper sections 50 50 from lower sections5050'. The upper sections 5050' are slightly recessed at their endsurfaces 5454. Normally, therefore, the lower sections 52-52' of thetiles tend to contact one another leaving a small space between theupper sections 5050'. The spline 28 is longitudinally slidable along themain beam flange 26 by the employment of a very thinv strong steel blade53 as shown in .FIG. 3. The joint between lower sections 5252 of thetiles is advantageously offset slightly (to the right of the beamportion 47 below rib 46) by the laterally protruding rib section 46which engages the upper tile section 50. Therefore, when the thin blade53 is inserted, it can conveniently extend upwardly alongside of theportion 47 of the web 44 until it reaches the rib section 46 and in thisway the user is assured that the edge of the blade 53 has secured amechanically positive engagement with the end of the slidable spline 28.Thus, the user can conveniently push the slidable spline along theflange 26 without fear that the blade 53 may suddenly skid past thespline 28.

The lateral protrusion 46 of the web of the main supporting beam 16 isso sized that it will abut the upper section 50 of the adjoining tile 18and actually force a slight offset of the joint between the lowersections 52-52' just sufficiently to enable insertion of the thin blade53 and yet not so much as to lose aesthetic appeal of the ceiling. Theprotrusion 46 as shown in the FIGS. 3 and 4 is rectangular in form andextends longitudinally along the web. It is possible to utilizean'effectively similar protrusion of somewhat different shape, but therectangular shape is preferred as will be explained in relation to FIG.12.

A further feature illustrated in FIG. 3 is the selective spacing of thecrossbars 36 from the main supporting beam 16. Note that each crossbar36 is provided with a cutout sized to permit longitudinal movement ofthe spline. In addition, the crossbar web ends 56 terminate short of themain beam 16 by the distance A, which is less than the spacing B betweenthe crossbar flange and the spline 28.

Thus, in the event a crossbar creeps up to the main beam 16, sufiicientspace remains for the spline 28 to slide without interference along theflange 26 of the beam. On the other hand, it is desired that thecrossbar flange 40 commences its support of a tile as closely aspossible to the spline 28. The reason for this resides in the nature ofmost tiles, which generally are brittle and do not readily withstand atensile stress. Since the midsection of tiles located between beams isessentially supported by crossbars 36 and since the crossbars do notdirectly rest upon the beam 16 a concentrated tensile force is appliedto the tile such as at support point 58 thereof.

This supporting force at 58 results in a force applied along a momenthaving a length approximately as indicated by the spacing L. By making Las small as possible, tile rupture is avoided.

FIG. 5 illustrates back-toback mounting of a pair of crossbars 36between removable sections. It is noted that each crossbar flange 40 isprovided with a plurality of protrusions 60 which are sized and shapedto snugly fit the cross flanges 40 with reduced vertical play withineach tile kerf and thus maintain the tiles between the main beams 16 inhorizontal alignment.

FIG. 6 illustrates that the protrusions 66) are not continuous, butcomposed of discrete bumps. Although a longitudinal protrusion could beemployed, the use of discrete protrusions 60 facilitates insertion of across flange 40 into the tile kerfs 33, which due to productiontolerances of acoustical tiles are not always exactly uniform in crosssection.

FIG. 7 illustrates the removal of a tile section as defined by a pair oftiles 18-48 and a pair of crossbars 36-36. First by the employment ofthe thin blade 53 as shown in FlG. 3, the two splines 28in FIG. 7 areslid along the respective flanges 26 of the main supporting beams 16-16,thereby permitting the left portion of the ceiling section to drop freeof the left supporting beam 16 as seen in FIG. 7. As soon as the leftend of the removable tile section has lowered enough to clear thesupporting beam 16, the tile kerf at the other end of the ceilingsection may be cleared from the flange 26 of the right supporting beam16 by applying a transverse motion as indicated by arrow 62. In thismanner, both tiles l8ll8' along with both crossbars 36-36 are removedand an enlarged access space to the plenum area above the ceiling isprovided. In this example this access space is 2 feet wide,corresponding to S in FIG. 1, and the access space can be made as longas may be desired by removing more than one of the ceiling sections inthe manner as described.

It is to be understood that when these ceiling sections are held inplace by the slidable splines 28, they are locked in place so that theycan neither be lifted up by hand nor by differential air pressure ordrafts of wind and they cannot be lowered. In other words, they arepositively locked in place when they are in their installed positions,and yet an enlarged access can be obtained wherever desired by buildingmaintenance personnel.

Spacer bars 24, as previously explained, both maintain accurate spacingbetween the supporting beams, as well as rigidly holding the beams 16against twisting. The spacer bars are located at intervals along themain supporting beams. For instance, in practical dimensions the spacerbars may be located every ID. to feet, whereas the removable ceilingsections are generally 2 feet wide.

Each spacer bar 24 is easily attached to a beam for quick assembly ofthe ceiling structure. This is accomplished by providing each spacerbar, prior to assembly as shown in FIG. 8B with a pair of T-shaped slots64 having an enlarged rectangular heaclspace sized to snugly enclose thebox beam section 42 of the main supporting beam 16. As shown in FIG. 83,after engagement of the spacer bar onto a beam 16 the slot 64 alsosnugly clamps against a portion of the beam web 44 below the rectangularbeam section 42. This snug enclosure of a beam 16 by the spacer bar 24is accomplished by initially providing the spacer bar with a bendabletab 66 originally in the bent-up position as indicated in FIGS. 8A and88 at 68.

With the tab 66 in the initial position at 68 the beam channel 42 can beengaged into the slot 64 and after such placement the tab 66 is bentdown along multiple fold lines 70 and 71 to a generally vertical planarposition to firmly lock or cap ture the beam in position relative to thespacer bar. This bending engagement is easily accomplished with a metalgripping tool such as a pair of pliers. It is noted that the tab 66 maybe bent in place with a single fold line 70 which may be placed at otherlocations for minimum interference during bending. The T-shaped slot 64is further provided on the vertical stem portion of the T-shape withopposed indentations at 73 to assure double pairs of web-gripping points7575' on opposite sides of the web 44.

When desired, the main supporting beam may alternately be attached tothe conventional structural channels by employing easily applied clips.FIGS. 9 through 11 illustrate such a clip 72 which is attached to astructural channel member 74 which is either suspended from or attachedto the building structure. The clip 72 is formed with an upper bendableflange 76 which may be wrapped by bending over the end of a flange 78 onthe structural channel member 74. The depending portion 80 of the clipis provided with a T-shaped slot 64 (FIG. 8B) and sized to snugly engagethe rectangular channel section 42 of the beam 16 as well as a portionof the beam web 44 similar to the spacer bar 24 of FIG. 8.

The clip '72 is thus provided with a bendable tab 83 initially bentalong the fold lines 84 and 85 to allow insertion of the beam 16 in slot82. Subsequently, the beam is captured in the slot by bending the tab asindicated in FIG. 10. It is seen that the lower portion 86' ofstructural channel member 74 rests against the upper box beam section42, and in this manner the horizontal alignment of the beams 16 isdetermined by the orientation of the channel member 74. However, asillustrated in FIG. 11 at 72A, the clip may also be elongated.

The advantage of utilizing a rectangular shaped protrusion 46 in the web44 of the main supporting beam 16 maybe appreciated from reference toFIG. 12. As shown in this figure a channel 88 is effectively defined bythe rectangular protrusion upper edge 89, the planar portion of the web44, and the lower surface 90 of the rectangular box beam section 42. Abeam splice 92 sized to fit in snug relationship into this channel maybe advantageously used to reinforce the main beam 16 for interconnectionwith another main beam aligned therewith. The splice 92 for this purposeis provided with laterally extending tabs 94 which after insertion intosuitable apertures in the webs of beams 16 are bent to lock the spliceonto the beams 16. The splice-coupled main supporting beams 16 arerigidly held as well as maintained in proper alignment.

Having thus described a new ceiling structure, several advantagesthereof now readily appear. The employment of enlarged removable tilesections facilitates assembly of the suspended ceiling. Substantialaccess areas are possible with the ceiling structure of this invention,yet without loss of rigidity with the employment of spacer bars. Thespacer bars both accurately locate main supporting beams parallel to oneanother as well as clamp the suspended structure in a mechanically rigidposition. The main supporting beams 16 having box beam sections 46 arestrong, stiff and yet are light in weight. Further horizontal alignmentand rigidity are obtained by selective shaping of the main supportingbeams to accommodate splices sized to fit in channels of the supportingbeams. The splices and spacer bars are easily installed to provide aneconomic properly aligned, rigid suspended ceiling structure.

What is claimed is:

1. In a suspended ceiling assembly formed of selectively removabletiles, each having peripherally located kerfs and having horizontallymounted parallel spaced longitudinal supporting beams, each beam havinga longitudinal web and a horizontally disposed longitudinaltile-supporting flange extending generally transversely from one side ofthe lower edge of the web and sized to fit within tile kerfs to supporta plurality of tiles, supporting splines slidably mounted on thetile-supporting flange for sliding movement therealong and within tilekerfs, each of said splines having a tile-supporting member extendinggenerally transversely from the web on the other side thereof and withthe member located generally coplanar with the supporting flange forsliding within tile kerfs, said splines having lengths smaller than thetile dimensions supported by the supporting flange for tile removal uponthe longitudinal movement of a spline along the supporting flange, theimprovement comprising crossbars mounted generally transversely to andbetween webs of adjacent supporting beams, said crossbars being sizedand shaped to fit between adjacent supporting beam webs to assureunobstructed longitudinal movement of splines, with each of saidcrossbars further having a cross-tile-supporting flange located ingeneral coplanar relationship with the supporting beam flange andextending generally transversely from a side of the lower edge of thecrossbar to fit within tile kerfs, aid crossbars being removable alongwith tiles upon selective longitudinal movement of splines along flangesof the supporting beams, the cross flanges of the crossbars being sizedto terminate with selective clearance from the webs of the longitudinalsupporting beams to permit free longitudinal movement of the splineswith the webs of the crossbars having an effective length sufficient tomaintain clearance of cross flanges from the longitudinally movingsplines.

2. The assembly as claimed in claim 1, wherein the cross flanges of thecrossbars are provided with vertical protrusions sized to locate saidcross flange in tile kerfs with reduced vertical play between tiles andcrossbars and maintain the tile portions between supporting bars inhorizontal alignment.

3. The assembly as claimed in claim 2, wherein the vertical protrusionsare discreet portions with limited longitudinal dimensions, saidcrossbar flanges providing tile support between supporting beams.

4. An acoustic ceiling assembly formed of selectively removable acoustictile sections with tiles having peripherally located kerfs comprisinghorizontally mounted parallel longitudinal supporting beams, each beamhaving a longitudinal web and a horizontally disposed longitudinaltile-supporting flange extending generally transversely from one side ofthe lower edge of the web and sized to fit within tile kerfs to supporta plurality of tiles, supporting splines slidably mounted on thetile-supporting flange for sliding movement therealong and within tilekerfs, each of said splines having a tile-supporting member extendinggenerally transversely from the web on the other side thereof and withthe member located generally coplanar with the supporting flange forsliding within tile kerfs, said'splines having lengths smaller than thetile dimensions supported by the supporting flange for tile removal uponthe longitudinal movement of a spline along the supporting flange,crossbars each mounted generally transversely between webs of adjacentsupporting beams, said crossbars having longitudinal webs of a length tofit between adjacent supporting beam webs and selectively shaped toassure unobstructed longitudinal movement of splines, with each of saidcrossbars further having a crossbar-supporting flange located in generalcoplanar relationship with the supporting beam flange and extendinggenerally transversely from a side of the lower edge of the web of thecrossbar to fit within tile kerfs, said crossbar flanges providing tilesupport between supporting beams, said tile support commencing at apoint spaced from the beams by a distance sufficient to permitunobstructed movement of splines, said crossbars being removable alongwith tiles therebetween upon selective longitudinal movement of splinesalong flanges of the supporting beams.

5. The assembly as claimed in claim 4 and further including spacer barsmounted between adjacent supporting beams to maintain said crossbars inefi'ectively close supporting relationship with splines and supportingbeam flanges.

6. The assembly as claimed in claim 5 wherein the spacer bars areprovided at the ends thereof with bendable tabs sized to engage thesupporting beams.

7. The assembly as claimed in claim 5 wherein the upper portions of thewebs of supporting beams are selectively en larged to form a grippableedge, and wherein the spacer bars are provided at ends thereof with aslot sized to snugly engage the grippable edge.

8. The assembly as claimed in claim 7 wherein the spacer bars areprovided with laterally bendable tabs located to enlarge the slots forinsertion of the beam-grippable edge therein, and to capture the beamwithin the slot upon a substantially coplanar bending of a tab.

9. The assembly as claimed in claim 8 wherein the grippable beam edge isrectangularly shaped and the slot is rectangular with the tab sized tosnugly engage a portion of the beam web upon a coplanar bending of thetab.

10. The assembly as claimed in claim 4 wherein each of the webs of thesupporting beams are provided with a longitudinally extending transverselateral protrusion generally located opposite tiles for slightdisplacement thereof to enhance accessibility to splines.

11. The assembly as claimed in claim 10 wherein said lateral protrusionis formed of a longitudinally extending substantially rectangulardeformation in the supporting member web.

12. The assembly as claimed in claim 10 wherein the supporting beam isfurther provided with an upper enlargement sized to-define with the weband the lateral enlargement an open channel, and beam splices sized tosnugly fit within the channel for beam support.

13. The assembly as claimed in claim 4 and wherein the beams at theupperweb end thereof are provided with an enlarged grippable edge andbeam clips having slots sized to capture the grippable beam edge, saidclips having laterally bendable tabs located to enlarge the clip slotsfor grippable edge insertion with said edge being captured in the slotupon generally planar closure of the laterally bendable tab.

14. The assembly as claimed in claim 13 wherein the upper end of theclip includes a transversely extending flange having a bendable lip endfor clip mounting.

15. An acoustic ceiling assembly formed of selectively removableacoustic tiles having peripherally located kerfs comprising horizontallymounted parallel-spaced longitudinal supporting beams, each beam havinga longitudinal tile-supporting flange extending generally transverselyfrom one side of the lower edge of a web and sized to fit within tilekerfs to support a plurality of tiles on said one side, supportingsplines slidably mounted on the tile-supporting flange for slidingmovement therealong and within tile kerfs, each of said splines having atile-supporting member extending generally transversely from the web onthe other side thereof and with the member located generally coplanarwith the supporting flange for sliding within tile kerfs on said otherside, said splines having lengths smaller than the tile dimensionssupported by the supporting flange for tile removal upon thelongitudinal movement of a spline along the supporting flange, the webof each of said supporting beams being provided with a laterallyextending protrusion protruding from said other side of said web fromsaid flange, said protrusion being located at tile height on the web onone side only for lateral displacement of the joint between tiles by apreselected distance toward said other side to facilitate insertion of athin blade in said joint for longitudinal movement of splines from belowof the ceiling structure.

16. The acoustic ceiling assembly as claimed in claim 15 wherein thelongitudinal protrusion is located on the other side of the web oppositeof the flange side.

17. An acoustic ceiling assembly formed of selectively removableacoustic tiles having peripherally located kerfs comprising horizontallymounted parallel-spaced longitudinal supporting beams, each beam havinga longitudinal web and a horizontally disposed longitudinaltile-supporting flange extending generally transversely from one side ofthe lower edge of the web and sized to fit within tile kerfs to supporta plurality of tiles, supporting splines slidably mounted on thetile-supporting flange for sliding movement therealong and within tilekerfs, each of said splines having a tile-supporting member extendinggenerally transversely from the web on the other side thereof and withthe member located generally coplanar with the supporting flange forsliding withintile kerfs, said splines having lengths smaller than thetile dimensions supported by the supporting flange for tile removal uponthe longitudinal movement of a spline along the supporting flange, theweb of each of said supporting beams being provided with a laterallyextending rectangular cross-sectional shaped protrusion on the web andlocated at tile height for lateral displacement of tiles by apreselected distance to facilitate longitudinal movement of splines frombelow of the ceiling structure, the upper part of the beam terminatingin a rectangular enlargement sized to define with the rectangularprotrusion an open longitudinal splice-retaining channel, and a splicesized to snugly fit within the splice channel to maintain. beams inhorizontal alignment.

18. In an acoustical ceiling assembly formed of selectively removableacoustic tiles having peripherally located kerfs and includinghorizontally mounted parallel-spaced longitudinal supporting beams, eachbeam having a longitudinal web and a horizontally disposed longitudinaltile-supporting flange extending generally transversely from one side ofthe lower edge of the web and sized to fit within tile kerfs to supportthe tiles on said one side thereof and with tile-supporting splineslongitudinally slidably mounted on the flange for sliding movementtherealong and within tile kerfs, the splines each having atile-supporting member extending generally transversely from the web onthe opposite side thereof from said flange for supporting tiles on saidopposite side, the improvement comprising a lateral protrusion extendinglaterally of the web of the longitudinal supporting beams on one sideonly of the web, said protrusion being located on the opposite sidethereof from said flange, said lateral protrusion being sized andlocated to engage the end surfaces of the tiles above the kerf on saidopposite side for producing a slight offset of the joint between thetiles on said one side and opposite side of said web, said offset of thejoint being in a direction toward said opposite side to enable insertionof a thin blade upwardly through said offset joint and beside said webfor engagement with a spline to produce sliding movement thereof forselective removal of acoustic tiles.

19. In an acoustical ceiling assembly, the improvement as claimed inclaim 18, in which said lateral protrusion extends longitudinally of theweb of the supporting beams.

20. In an acoustical ceiling assembly, the improvement as claimed inclaim 18, in which said lateral protrusion is a rib extendingcontinuously longitudinally of the web of the supporting beams on oneside only of the web and positioned above the lower edge of the web tobe engaged by and thereby to limit the upward insertion of a thin bladethrough said offset joint.

21. In an acoustical ceiling assembly, the improvement as claimed inclaim 18, in which the lateral protrusion is positioned below the upperedge of the web of the supporting beams and extends continuouslylongitudinally of the web, the upper edge of the web has an enlargementextending longitudinally therealong, and said enlargement, said lateralprotrusion and the web extending therebetween define an open channellocated above said protrusion, said open channel facing toward saidother side of the web and being adapted to snugly receive abeam-splicing element extending longitudinally therein, said openchannel providing longitudinal alignment and vertical support of suchbeam splice element fitting snugly therein.

1. In a suspended ceiling assembly formed of selectively removable tiles, each having peripherally located kerfs and having horizontally mounted parallel spaced longitudinal supporting beams, each beam having a longitudinal web and a horizontally disposed longitudinal tile-supporting flange extending generally transversely from one side of the lower edge of the web and sized to fit within tile kerfs to support a plurality of tiles, supporting splines slidably mounted on the tile-supporting flange for sliding movement therealong and within tile kerfs, each of said splines having a tile-supporting member extending generally transversely from the web on the other side thereof and with the member located generally coplanar with the supporting flange for sliding within tile kerfs, said splines having lengths smaller than the tile dimensions supported by the supporting flange for tile removal upon the longitudinal movement of a spline along the supporting flange, the improvement comprising crossbars mounted generally transversely to and between webs of adjacent supporting beams, said crossbars being sized and shaped to fit between adjacent supporting beam webs to assure unobstructed longitudinal movement of splines, with each of said crossbars further having a cross-tile-supporting flange located in general coplanar relationship with the supporting beam flange and extending generally transversely from a side of the lower edge of the crossbar to fit within tile kerfs, said crossbars being removable along with tiles upon selective longitudinal movement of splines along flanges of the supporting beams, the cross flanges of the crossbars being sized to terminate with selective clearance from the webs of the longitudinal supporting beams to permit free longitudinal movement of the splines with the webs of the crossbars having an effective length sufficient to maintain clearance of cross flanges from the longitudinally moving splines.
 2. The assembly as claimed in claim 1, wherein the cross flanges of the crossbars are provided with vertical protrusions sized to locate said cross flange in tile kerfs with reduced vertical play between tiles and crossbars and maintain the tile portions between supporting bars in horizontal alignment.
 3. The assembly aS claimed in claim 2, wherein the vertical protrusions are discreet portions with limited longitudinal dimensions, said crossbar flanges providing tile support between supporting beams.
 4. An acoustic ceiling assembly formed of selectively removable acoustic tile sections with tiles having peripherally located kerfs comprising horizontally mounted parallel longitudinal supporting beams, each beam having a longitudinal web and a horizontally disposed longitudinal tile-supporting flange extending generally transversely from one side of the lower edge of the web and sized to fit within tile kerfs to support a plurality of tiles, supporting splines slidably mounted on the tile-supporting flange for sliding movement therealong and within tile kerfs, each of said splines having a tile-supporting member extending generally transversely from the web on the other side thereof and with the member located generally coplanar with the supporting flange for sliding within tile kerfs, said splines having lengths smaller than the tile dimensions supported by the supporting flange for tile removal upon the longitudinal movement of a spline along the supporting flange, crossbars each mounted generally transversely between webs of adjacent supporting beams, said crossbars having longitudinal webs of a length to fit between adjacent supporting beam webs and selectively shaped to assure unobstructed longitudinal movement of splines, with each of said crossbars further having a crossbar-supporting flange located in general coplanar relationship with the supporting beam flange and extending generally transversely from a side of the lower edge of the web of the crossbar to fit within tile kerfs, said crossbar flanges providing tile support between supporting beams, said tile support commencing at a point spaced from the beams by a distance sufficient to permit unobstructed movement of splines, said crossbars being removable along with tiles therebetween upon selective longitudinal movement of splines along flanges of the supporting beams.
 5. The assembly as claimed in claim 4 and further including spacer bars mounted between adjacent supporting beams to maintain said crossbars in effectively close supporting relationship with splines and supporting beam flanges.
 6. The assembly as claimed in claim 5 wherein the spacer bars are provided at the ends thereof with bendable tabs sized to engage the supporting beams.
 7. The assembly as claimed in claim 5 wherein the upper portions of the webs of supporting beams are selectively enlarged to form a grippable edge, and wherein the spacer bars are provided at ends thereof with a slot sized to snugly engage the grippable edge.
 8. The assembly as claimed in claim 7 wherein the spacer bars are provided with laterally bendable tabs located to enlarge the slots for insertion of the beam-grippable edge therein, and to capture the beam within the slot upon a substantially coplanar bending of a tab.
 9. The assembly as claimed in claim 8 wherein the grippable beam edge is rectangularly shaped and the slot is rectangular with the tab sized to snugly engage a portion of the beam web upon a coplanar bending of the tab.
 10. The assembly as claimed in claim 4 wherein each of the webs of the supporting beams are provided with a longitudinally extending transverse lateral protrusion generally located opposite tiles for slight displacement thereof to enhance accessibility to splines.
 11. The assembly as claimed in claim 10 wherein said lateral protrusion is formed of a longitudinally extending substantially rectangular deformation in the supporting member web.
 12. The assembly as claimed in claim 10 wherein the supporting beam is further provided with an upper enlargement sized to define with the web and the lateral enlargement an open channel, and beam splices sized to snugly fit within the channel for beam support.
 13. The assembly as claimed in claim 4 and wherein the beams at the upper web end thereof are provided with an enlarged griPpable edge and beam clips having slots sized to capture the grippable beam edge, said clips having laterally bendable tabs located to enlarge the clip slots for grippable edge insertion with said edge being captured in the slot upon generally planar closure of the laterally bendable tab.
 14. The assembly as claimed in claim 13 wherein the upper end of the clip includes a transversely extending flange having a bendable lip end for clip mounting.
 15. An acoustic ceiling assembly formed of selectively removable acoustic tiles having peripherally located kerfs comprising horizontally mounted parallel-spaced longitudinal supporting beams, each beam having a longitudinal tile-supporting flange extending generally transversely from one side of the lower edge of a web and sized to fit within tile kerfs to support a plurality of tiles on said one side, supporting splines slidably mounted on the tile-supporting flange for sliding movement therealong and within tile kerfs, each of said splines having a tile-supporting member extending generally transversely from the web on the other side thereof and with the member located generally coplanar with the supporting flange for sliding within tile kerfs on said other side, said splines having lengths smaller than the tile dimensions supported by the supporting flange for tile removal upon the longitudinal movement of a spline along the supporting flange, the web of each of said supporting beams being provided with a laterally extending protrusion protruding from said other side of said web from said flange, said protrusion being located at tile height on the web on one side only for lateral displacement of the joint between tiles by a preselected distance toward said other side to facilitate insertion of a thin blade in said joint for longitudinal movement of splines from below of the ceiling structure.
 16. The acoustic ceiling assembly as claimed in claim 15 wherein the longitudinal protrusion is located on the other side of the web opposite of the flange side.
 17. An acoustic ceiling assembly formed of selectively removable acoustic tiles having peripherally located kerfs comprising horizontally mounted parallel-spaced longitudinal supporting beams, each beam having a longitudinal web and a horizontally disposed longitudinal tile-supporting flange extending generally transversely from one side of the lower edge of the web and sized to fit within tile kerfs to support a plurality of tiles, supporting splines slidably mounted on the tile-supporting flange for sliding movement therealong and within tile kerfs, each of said splines having a tile-supporting member extending generally transversely from the web on the other side thereof and with the member located generally coplanar with the supporting flange for sliding within tile kerfs, said splines having lengths smaller than the tile dimensions supported by the supporting flange for tile removal upon the longitudinal movement of a spline along the supporting flange, the web of each of said supporting beams being provided with a laterally extending rectangular cross-sectional shaped protrusion on the web and located at tile height for lateral displacement of tiles by a preselected distance to facilitate longitudinal movement of splines from below of the ceiling structure, the upper part of the beam terminating in a rectangular enlargement sized to define with the rectangular protrusion an open longitudinal splice-retaining channel, and a splice sized to snugly fit within the splice channel to maintain beams in horizontal alignment.
 18. In an acoustical ceiling assembly formed of selectively removable acoustic tiles having peripherally located kerfs and including horizontally mounted parallel-spaced longitudinal supporting beams, each beam having a longitudinal web and a horizontally disposed longitudinal tile-supporting flange extending generally transversely from one side of the lower edge of the web and sized to fit within tile kerfs to support the tiles on saiD one side thereof and with tile-supporting splines longitudinally slidably mounted on the flange for sliding movement therealong and within tile kerfs, the splines each having a tile-supporting member extending generally transversely from the web on the opposite side thereof from said flange for supporting tiles on said opposite side, the improvement comprising a lateral protrusion extending laterally of the web of the longitudinal supporting beams on one side only of the web, said protrusion being located on the opposite side thereof from said flange, said lateral protrusion being sized and located to engage the end surfaces of the tiles above the kerf on said opposite side for producing a slight offset of the joint between the tiles on said one side and opposite side of said web, said offset of the joint being in a direction toward said opposite side to enable insertion of a thin blade upwardly through said offset joint and beside said web for engagement with a spline to produce sliding movement thereof for selective removal of acoustic tiles.
 19. In an acoustical ceiling assembly, the improvement as claimed in claim 18, in which said lateral protrusion extends longitudinally of the web of the supporting beams.
 20. In an acoustical ceiling assembly, the improvement as claimed in claim 18, in which said lateral protrusion is a rib extending continuously longitudinally of the web of the supporting beams on one side only of the web and positioned above the lower edge of the web to be engaged by and thereby to limit the upward insertion of a thin blade through said offset joint.
 21. In an acoustical ceiling assembly, the improvement as claimed in claim 18, in which the lateral protrusion is positioned below the upper edge of the web of the supporting beams and extends continuously longitudinally of the web, the upper edge of the web has an enlargement extending longitudinally therealong, and said enlargement, said lateral protrusion and the web extending therebetween define an open channel located above said protrusion, said open channel facing toward said other side of the web and being adapted to snugly receive a beam-splicing element extending longitudinally therein, said open channel providing longitudinal alignment and vertical support of such beam splice element fitting snugly therein. 